用横向塞曼激光作光源构成的Dammann光栅多普勒干涉仪有利于降低热膨胀影响,测量过程中干涉臂长不变、便于克服折射率漂移,具有0.7 nm分辨率。分析了光栅退偏效应的影响,与差动双频激光干涉仪进行了比对。实验结果表明,光栅间距光学8细分等间隔,当光栅栅距为20μm时其测量非线性误差不超过25 nm

A Dammann grating interferometer using transverse Zeeman laser as light resource is developed in this paper.It takes advantages of reducing the effect of thermal expansion.Drift of the air refraction index can be easily conquered due to equivalent beam length.It is an attractive configuration with resolution of 0.7 nm.The error caused by the depolarization effect of the grating is analyzed.Calibration experiment between this grating interferometer and a differential dual-frequency interferometer has been implemented.The experimental results show that the equal divisions of the grating pitch by 8 times via optical system and the nonlinearity error is no more than 25 nm when the grating pitch equals 20 μm.